Railway traffic controlling apparatus



Aug. 15, 1939. c, w FAILOR 2,169,603

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 23, 1938 3 Sheets-Sheet1 IN NTOB Charle Fazlar BY 2 HIS ATTORNEY Aug. 15, 1939. c. w. FA'lLoRRAILWAY TRAFFIC CONTROLLING APPARATUS s Sheets-Sheet 2' Filed Feb. 23,1938 $5 Q25 owvwn Patented Aug. 15, 1939 UNITED s'ra'rss PATENT OFFICERAILWAY TRArrro CONTROLLING APPARATUS Application February 23, 1938,Serial No. 191,939

20 Claims.

My invention relates to railway trafiic controlling apparatus of theclass wherein coded track circuit energy is utilized to control eitheror both wayside signals and train-carried governing devices and moreparticularly it relates to the trackway portions of such apparatus andto the manher of organization thereof.

One object of my invention is to provide a novel and improved form ofsuch organization.

Another object is to make a novel utilization of counting-chain relaysin decoding apparatus for the control of wayside signals.

An additional object is to provide trackway codes utilizing spacedpulses of both normal and reversed polarity energy which are e'fiectiveto control both my improved wayside decoders and train-carried decodersof the usual frequencyselective type.

A further object is to make provision for applying the trams-governingapparatus to automatic signal blocks which both do and do not containcut sections.

A still further object is to provide for the clearing of track circuitsof out sections without interfering with the desired control of thewayside and train-carried decoding equipments.

I shall describe one representative form of traffic controllingapparatus embodying my invention and shall then point out the novelfeatures thereof in claims. This illustrative embodiment of my inventiveimprovements is disclosed by the accompanying drawings, in which:

Figs. 1a and 1b are diagrammatic views which when placed end to end inthe order named represent a stretch of railway track equipped withtrafiic-controlling apparatus embodying my inventicn;

Fig. 2 is a diagrammatic representation of some trackway-energy codeswhich may be used to control the apparatus of Figs. 1ab;

Fig. 3 is a series of views indicating one manner in which thecoding-device contacts for producing the four codes represented in Fig.2 may be arranged and actuated;

Fig. 4 is a diagrammatic representation of the effect of the presence ofa train in a block upon the track relay and the waysidetraffic-controlling relays of a number of blocks and also upon the cabsignals of a following train; and

Fig. 5 is a diagrammatic representation of cab signal circuits ofconventional frequency-selective character which are suitable forcooperation with and control by the trackway apparatus 'of the myinvention are there disclosed as being incorporated in a combinedautomatic block and cab signaling system for a track i2 over whichtrafiic moves in the single direction designated by the arrows, or fromleft toright in the dia- 5 grams. Insulated joints 3 divide the rails ofthe protected stretch of this track into the customary successivesections LLa, LaM, etc. In the stretch of track which is represented inFigs. 1a and 1b, the locations L and M mark the points of main signalblock division while the location La represents a subdivision of one ofthese main signal blocks. This particular subdivision is cocasioned by ahighway 3 which crosses the track within the confines of the block LMand with which the usual crossing protecting signals XS are associated.

Positioned at the entrance of each of the main signal blocks is awayside signal S which is adapted to indicate to an approaching trainthe nature of the traflic conditions in the blocks immediately ahead.The block-subdividing location represented at La, being within theconfines of the block LM which is protected by signal SI, has only thehighway crossing protection devices XS and no wayside signal associatedwith it.

The wayside signals S shown by way of illustration at the locations Land M are of a wellknown color-light type and each comprises an upperunit of three lamps G, Y and R, and a lower unit of two lamps G and B.When lighted the two lamps G and R of both units respectively displaythe colors of green and red and lamp Y of the upper unit displays thecolor of yellow. These signals are arranged to show any one of fourdifferent aspects which respectively signify the indications of clear,caution, slow and stop. For purposes of explanation it will be assumedthat these particular indications are identified with the aspects ofgreen-over-red, yellow over-green, yellow-over-red and red-over-red, asrespectively represented at locations I, J, K and L in Fig. 4.

The rails of each of the referred to sections of track form a part of a.track circuit which is adapted to transmit train-control energy in the.usual manner. In the particular arrangement represented each of thesetrack circuits further includes the control winding of a track relay TR.which is installed at the traflic-entering end of the section and atrack transformer TT connected, through the usual current-limitingreactor ?6, with the rails thereof at the traffic-leaving or exit end ofthe section.

Operating energy is supplied to each track cirtact I80 and conductor I5.

cuit through the transformer TT. This energy may, of course, be derivedfrom any suitable alternating current source and distributed to theseveral locations of track circuit division L, La, M, etc., by the aidof a transmission circuit (not shown) extending along the right of wayin the usualmanner. In the diagrams, characters B and C designatepower-distributing terminals which are supplied from one such source,the frequency of which will be assumed to be of the usual signalpowervalue of 60 or 100 cycles per second.

Interposed between the power-source terminals B and C and the energizingcircuits for the track transformers 'IT are supply'transformers 8 thesecondary winding of each 'of which is provided with a mid-tap 9. Oneside of the primary winding of each track transformer TT is directlyconnected, by means of a conductor II, with this mid-tap of theassociated supply transformer 8 and the other side of the tracktransformer primary is selectively connected, through a conductor I2 andthe contacts of a code transmitter CT,

': sively repeated. These code-cycle pulses are produced by'interrupting the rail-supply circuit a definite number of times perminute and by reversing, during a portion of each cycle, the relativeinstantaneous polarity of the energy which is fed into'the circuit.

The particular transmitter shown at CT employs a circuit makingeand-breaking contact 80 to produce the slow code, a second contact I toproduce the caution code, and a third contact I80 to produce the clear'code. By a motor or other suitable mechanism (not shown in detail),these contacts are continuously actuated at three different speeds whichfor purposes of explanation will be assumed to be such as respectivelyto provide the referred to codes of 80, 120 and 180 energy pulsesper'minute. All of these transmitters are arranged to operatecontinuously and to this end they are constantly supplied withsuitableactuating energy from source B-C.

Selection of which one of the three coding contacts above named isincluded in the energizing circuit of the associated track transformerT1 is effected by contacts I4 of a group of traflic-governing relays H,D and DD which form a part of the equipment installed at each of thewayside signal locations L, M, etc. When the contacts 7 of both of therelays H and D are picked up the track transformer receives energy ofthe clear code through a circuit which includes coding con- When thecontacts of relay Hare picked. up and those of relay D are released, thetransformer circuit includes coding contact I20 and a conductor I6 andthen is supplied with energy of the caution code. 7 Finally,

when the contacts of both of the relays H and D V cludes coding contact80 and a conductor H.

In all three instances the postive or normal- I polarity pulses of codeenergy are suppliedlfrom the upper half of the secondary of the supplytransformer 8 or portion thereof above the midtap 9, and the negative orreversed-polarity energy pulses are supplied from the lower half orportion of the winding below the tap 9. Polarity selection is determinedby whether the active coding contact (80, I20 or I80) is moved upwardlyor downwardly from the midway of neutral position which is representedin full lines in the diagrams.

One form of code-transmitter mechanism for" actuating these contacts inthe special way indi- L cated is shown in Fig. 3. There each of thecoding contacts is represented as being associated with a constantlyrotating cam shown immediately therebeneath and the periphery of whichis provided with regularly spaced lobes and depressions. As shown, the80-contact cam has three such lobes or protrusions and one depression,the I20- contact cam has three lobes and one depression, and theI80-contact cam has four lobes and two depressions. the 80 contactconnects conductor I! with the upper terminal of the supply winding twosuccessive times and with the, lower terminal of With this illustrativearrangement, a

the supply winding once during each code cycle;

the I20 contact connects conductor I6 three suc cessive times with theupper winding terminal duration of second and consecutive pulses are,

spaced by the same period of time; in the case of the I20 or cautioncode each of the pulses and spaces has a length of second; and in-thecase of the I80 or clear code each of the pulses and spacing periods hasa length of second.

From Fig. 2 it will further be seen that each com v plete cycle of the80 code has a total duration of 7 2% seconds, each complete cycle of theI20 code is 2 seconds in length, and each complete cycle of the I 80code also has a duration of 2' seconds This means that in producing theclear code of Fig. 2 the I80 contact cam of Fig. 3 must make revolutionsper minute; in producing the caution code the represented I20 contactcam must rotate at the same speed; and in producing the slow code therepresented 80 contact cam must operate at the slower speed of 26revolutions per minute. r

In a code transmitter of the particular type which is shown at CT inFig.1, the I80 and shown) at the above stated speed of 30 revolutions perminute. Because, however, of its requirement of a slower operating speed(26% R. P M.) V

selecting relay H or D can under no circumstance introduce into thefirst cycle of the newly selected code a number of normal-polaritypulses in excess of the preselected quantity. As will be seen presently,this precaution prevents the controlled wayside signal S from giving amomentary flash of a less restrictive indication on the occasion of anew code selection.

The circuits which are efiective during the transmission to the trackwayof both the normal and reversed polarity energy pulses of the firstthree or traflic-governing codes represented in Fig. 2 will now betraced. In all instances this transmission is to the rails of the tracksection to the rear of the section-dividing location where thetransmitting apparatus is installed and by way of the associated tracktransformer TT.

In the case of the 80 or slow code, the normal-polarity-pulse circuitextends from the upper terminal of the secondary winding of transformer8 through conductor 29, the coding contact 80 when in its uppermostposition, conductor II, released contact M of traffic-governing relay H,conductor I2, the primary of track transformer TT and conductor II backto the mid-tap 9 of the supply winding. The reversed-polarity pulsecircuit for this 88 code may be traced from the lower terminal of thereferred-to supply winding through conductors 38 and 3I, the codingcontact 88 when inits lowermost position, conductor II, released contactI4 of relay H, conductor I2, the primary of transformer TT and conductorI I back to the mid-tap 9 of the supply winding.

In the case of the I20 or caution code, the normal-polarity-pulsecircuit extends from the upper terminal of the secondary Winding oftransformer 8 through conductors 29 and 32, coding contact I29 in itsuppermost position, conductor IE, released contact I4 oftraffic-governing relay D, conductor 33, picked-up contact I4 of relayH, conductor I2, the primary of transformer TT and conductor II back tothe supply winding mid-tap 9. The reversed-polarity-pulse circuit forthis I28 code may be traced from the lower terminal of the referred-tosupply winding, through conductors 30 and 3 I, coding contact I20 whenin its lowermost position, conductor I6, released contact I4 of relay D,conductor 33, picked-up contact I4 of relay H, conductor I2, the primaryof transformer TT and conductor I I back to mid-tap 9.

In the case of the I80 or clear code represented in Fig. 2, thenormal-'polarity-pulse circuit extends from. the upper terminal of thesecondary of transformer 8 through conductors 29 and 32, the codingcontact I80 when in its uppermost position, conductor I5, picked-upcontacts Il of relays D and H in series, conductor I2, the primary oftransformer TT and conductor I I back to mid-tap 9. Thereversed-polarity-pulse circuit for this I80 code may be traced from thelower terminal of the referred to supply winding, through conductor 30,coding contact I89 when in its lowermost position, conductor I5,picked-up contacts I4 of relays D and H in series, conductor I2, theprimary of transformer TT and conductor II back to the mid-tap 9 of thesecondary of transformer 8.

In addition to selecting the coding of the energy which is suppliedtothe track circuit to the rear, the traffic-governing relays H, D andDD at each of the wayside signal locations also control the operation ofthe associated wayside signal S. This signal control is effected throughthe mediumof contacts. I8 .and I9.carried by the relays and included incircuits through which the signal lamps are selectively energized froma-suitable source of power, also designated in the diagrams by theterminals B and. C.

When the contacts of all three of the relays H, D and DD are picked upthe controlled wayside signal S shows the clear indication ofgreenover-red. The lighting circuit for the upper green lamp thenextends from the supply terminal B through front contacts I9 of allthree of the relays in series, conductor 22 and the lamp G back tosupply terminal C. The circuit for the lower red lamp similarly extendsfrom terminal B through front contacts I8 of relays H, D and DD inseries, conductor 23 and the lamp R back to the terminal C.

When the contacts of relays H and D are picked up and those of relay DDare released the controlled signal S shows the caution indicationyellow-over-green. The lighting circuit for the yellow lamp may betraced from the supply terminal B, through front contacts I9 of relays Hand D in series, conductor 24 and the lamp Y back to the supply terminalC. The circuit for the lower green lamp extends from terminal B, throughfront contacts I8 of relays H and Din series, back contact I8 of relayDD, conductor 25 and the lamp G back to the terminal C.

When the contacts of relay H only are picked up and those of relays Dand DD are released the wayside signal S displays the slow indication ofyellow-over-red. The circuit for the yellow lamp may now be traced fromterminal B, through front contact I9 of relay H, back contact IQ ofrelay D, conductor 24 and the lamp Y back to terminal 0. The circuit forthe lower red lamp now extends from terminal B through front contact I8of relay H, back contact I8 of relay D, conductor 23 and the lamp R backto terminal C.

Finally, when the contacts of all of the traffic governing relays H, Dand DD are released, the controlled wayside signal S displays the stopindication of red-over-red. The lighting circuit for the upper red lampextends from terminal B through back contact I9 of relay H, conductor25, and the lamp R back to terminal C. The circuit for'the lower redlamp may now be traced from terminal B through back contact I8 of relayI-I, conductor '23 and the lamp R back to. terminal C.

The particular one of the four just described positional combinationswhich is assumed by the contacts of the traffic-governing relays H, Dand DD at each signal location is determined by the character of theenergy which is received from the rails I and 2 of the advance tracksection by the control Winding of the track relay TR at that location.Cooperating with each of these track relays in its control of theassociated traffic-governing relays is decoding apparatus in the form ofcounting-chain relays IR, IRA, 2R, ZRA, 3R, 3RA and 4R and acycle-registering relay P. The counting-chain relays are arranged torespond distinctively to cycles of the clear, caution and slow trackwaycodes (represented in Fig. 2) and perform this function by counting thenumber of normal-polarity energy pulses in each of the code cycles whichis received from the trackway. In accordance with that number they setup-for the windings of relays H, D and DD energizing circuits which areselectively and periodically completed by the track relay in a mannerexplained in a later portion of this specification.

Each of the track relays represented at TR is of an alternating-currenttwo-element two-position type which responds only to normal-polarityenergy received from the track rails with which its control winding isshown as being directly connected. This relay distinguishes the polarityof the received energy by comparing it with a measure of thealternating-current voltage of the supply source BC which is constantlyimpressed upon a local or exciting winding 21. The particular relayshown is provided with a single contact 28 which is sufficiently quickacting in both the pick-up and release directions as to be able tochange its position in accurate synchronism with dition during each ofthe normal-polarity pulses.

of energy which the coding device CT supplies to the track transformerTT from the upper half of the secondary winding of the transformer 8.Finally, when the relay control winding receives energy of the negativeor reversed relative in-v stantaneous polarity the contact 28 is merelyurged more firmly into its back or released position. This is thecondition during each of the reversed-polarity pulses of trackway energywhich the coding device CT supplies from the lower half of the secondarywinding of the transformer 8.

The cycle-registering relay shown at P is ressponsive to eachuninterrupted series of positive or normal-polarity energy pulses of anyone of the three of the clear, caution and slow codes which are shown inFig. 2, and thus serves to register the individual cycles of any ofthose codes. Each time that the track relay contact 28 is in itspicked-up or front position the operating winding of this relay isenergized. As shown, this winding'is of the direct-current type andenergizing current therefor is supplied from an energy Source,designated by theterminals plus and minus, over a circuit which includesa conductor 36. a r

The contact 34 (and also 35 when used) of relay P is sufficiently slowacting in the releasing or drop-out direction as to bridge the offperiods which separate consecutive normal-polarity pulses in all threeof the clear, caution and slow trackway codes of Fig. 2.' At the sametime the magnitude of this drop-out delay is so limited as not to bridgethe intervalwhich is represented by the reversed-polarity pulses ofenergy which follow each series of normal-polarity pulses and complete,in the case of all of the three named codes, the cycle of which thesenormalpolarity pulses constitutethe beginning. In practice a releaseperiod of the order of second is found to meet both of the aboverequirements when traffic-governing codes of the illustrative characterpreviously described are used. The value stated is, it will be noted,substantially greater than the second off period (minimum limitingvalue) of the slow or 80 code and substantially less than the secondinterval (maximum limiting value) between successive trains or groups ofnormal-polarity pulses of th I80 or clear code.

At each location of a wayside signal S which guards a track blockcontaining a cut section, such as is occasioned by the highway crossingshown at point La in the blockL-M, a second auxiliary control relay T]?is also utilized for the purpose of controlling the relays XR whichgovern the operation of the highway crossing signals XS. As will beexplained in greater detail in a later portion of the specification,this relay registers the cycles of a fourth or detection code which isrepresented at the bottom of Fig. 2. Its

operating winding is controlled through a circuit which includes acontact 35 of the repeaterrelayP and it has a period of release delaywhich is sufficiently greater than that of relayP as to cause itscontacts to remain continuously picked-up as j long as a trackway codeis received.

At the entrances of track blocks which do not contain cut sections thisrelayTP is not required,

ence to their individual operation and coordina-' tion and then withreference to the manner in which they cooperate with the associatedtrack relay TR selectively to control the traffic-governing relays H, Dand DD.

In the particular counting chain represented,

these relays are arranged in two groups: one, including devices IR, 2R,3R and 4R, which counts the normal-polarity pulses of energy in eachcode .cycle; and another group, including relays. IRA,

2RA and 3RA, which registers the intervals which separate thesenormal-polarity pulses in each cycle of the received code. All of thecounting chain relays are shown as having direct-current operatingwindings which at proper times are supplied with current through pick-upand stick circuits which are connected with a diroot-current supplysource, again designated by the terminals plus and minus.

Initial actuation of the counting-chain relays is effected through theirpick-up circuits, all of which are controlled by the track relay TR. In

the case of relays IR, 2R, 3R and 4R which count the normal-polaritypulses of each code cycle, each pick-up circuit can be completed onlywhen contact 28 of relay TR is picked up. In addition to this contact28, the pick-up circuit for relay IR includes serially connectedcontacts 38 of the remaining six relays in the counting chain; that forrelay 2R includes serially connected contacts 39 of relays IR and IRA;that for relay 3R inincludes serially connected contacts 39 of relaysIR, IRA, 2R and 2RA; and that for relay 4R includes serially connectedcontacts 39 of all six of the relays which precede it in the countingchain. e V I In the case of relays IRA, ZRA and 3RA which count thenormal-polarity pulse-spacing intervals of each code cycle, each of thepick-up circuits can be completed only when the contact of the trackrelay TR is released. In addition to this contact 28, the pick-upcircuit for relay IRA includes a contact 40 of relay IR; that for relay2RA includes contacts 40 of relays IR, IRA and 7 2R in series; and thatfor relay 3RA includes serially-connected contacts 40 of all five of therelays which precede it in the counting chain.

Once the contacts of the counting chain relays are picked up, further orprolonged front closure of these contacts is effected through thebeforementioned stick circuits. All of these counting-chain stickcircuits are controlled by the cycle-registering or repeater relay P andeach can be completed only when contact 34 of that relay is picked up.In each instance, moreover, stick-circuit completion can be effectedonly when a contact 4| of the counting relay to which the circuitbelongs is moved upwardly into engagement with .a cooperating contact 42and also only when all of the counting relays beyond the given one inthe counting chain are deenergized to allow their members 42 to engagewith cooperating contacts 43.

The contacts just named are so arranged that as each counting relayactuates, it first sets up its own stick circuit at contact 4| and thenbreaks the stick circuit for the immediately preceding relay at contact43. Moreover, the contacts 38, 39 and 49 of these relays are so includedin the pick-up circuits of adjacent relays in the actuating sequencethat should any one of the relays fail to release its contacts operationof the counting chain beyond that point will be prevented.

For the purpose of controlling the traflic-governing relays H, D and DD,counting-chain relays ER, lRA, 2R, SR .and 4R are provided withadditional contacts 44 which form parts of circuits through which thewindings of the tramcgoverning relays are selectively supplied withpulses of energizing current. These circuits are more fully described ina later portion of the specification.

In examining the manner in which the counting-chain relays operate,assume first that the contacts of all of the relays in the chain occupytheir dropped out or released positions as represented in Fig, 1, thatcontact 28 of the associated track relay TR is also released, and thatthe contacts of the cycle-registering relay P are likewise released.These are the conditions which obtain just prior to the beginning ofeach cycle of any one of the three traffic-governing codes of Fig. 2which may be received from the trackway.

As the first normal-polarity energy pulse of one of these code cycles isreceived, track relay TR lifts its contact 28 to the front position andpicks up repeater relay P over a circuit which extends from the positivesupply terminal, through contact 28, conductor 36, and the winding ofrelay P back to the negative supply terminal. At the same time, thetrack relay TR also picks up counting chain relay IR over a circuitwhich extends from the positive supply terminal, through contact 23,conductors 36 and 46, back contacts 38 of relays 4R, 3RA, 3R, 2RA, 2Rand IRA in series, conductor 47 and the winding of relay IR back to thenegative supply terminal. In picking up, relay ER locks itself in, bymeans of contact 4|, over a stick circuit which extends from thepositive supply terminal through front contact 34 of relay P, conductor48, engaged contacts 42 and 43 of relays 4R, 3RA, 3R, 2RA, 2R and IRA inseries, engaged contacts 42 and 4| of relay IR, conductor 41 and thewinding of relay IR back to the negative supply terminal.

During the first ofi period or pulse-separating interval of the receivedcycle of traffic-governing code, contact 28 of the track relay TRreturns to its released position; the contacts of relay P remaincontinuously picked up, due to their slow-releasing characteristics(delay of second) which exceed the code off-period length (which is A;or secondsee Fig. 2); and chain relay IR remains picked up under theaction of its'own stick circuit. In dropping out at the beginning ofthis off period, contact 28 of the track relay picks up chain relay IRAover a circuit which may be traced from the positivesupplyterminaLthrough the back contact 28, conductc-r i lfrontcontact 48of relay IR, conductor 5| and the winding of relay IRA' back to thenegative supply terminal. As relay IRA picks up, it locks itself in overa stick circuit which extends from the positive supply terminal throughfront contact 34 of relay P, conductor 48, engaged contacts 12 and 43 ofrelays 4R, 3RA, 3R, 2RA, and ER in series, engaged contacts 42 and 4| ofrelay IRA, conductor 5| and the winding of relay IRA back to thenegative supply terminal. Due to the resulting interruption of its stickcircuit at contact 43 of relay IRA, relay IR now drops out.

As the second normal-polarity energy pulse of the traffic-governing codecycle is received, the track relay TR again picks up contact 28 andsupplies the winding of relay P with a second pulse of energizingcurrent. This is received before the release period of relay P hasexpired and it prolongs the continuous actuation of that relay. Atthe'same time the track relay also picks up counting relay 2R over acircuit which extends froin the positive supply terminal through frontcontact 28, conductors 36, 46 and 52, back contact 39 of relay IR, frontcontact 39 of relay IRA, conductor 53 and the winding of relay 2R backto the negative supply terminal. In actuating, relay 2R first completesits own stick circuit at contact 4| and then interrupts the stickcircuit for relay IRA at contact 43, thereby allowing that relay to dropout. The referred to stick circuit for relay 2R extends from thepositive supply terminal through front contact 34 of relay P, conductor48, engaged contacts 42 and 43 of relays 4R, 3RA, 3R and 2RA in series,engaged contacts 42 and 4| of relay 2R, conductor 53 and the winding ofrelay 2R back to the negative supply terminal.

During the second off period of the received cycle of traffic-governingcode, contact 28 of the track relay TR again returns to its releasedposition and picks up chain relay 2RA over a circuit which extends fromthe positive supply terminal through back contact 28 of relay TR,conductor 49, back contacts 40 of relays IR and IRA in series, frontcontact 40 of relay 2R, conductor 54 and the winding of relay 2RA backto the negative supply terminal. In actuating, relay 2RA first completesits own stick circuit and then breaks the stick circuit for relay 2R,thereby allowing that relay to drop out. The referred to stick circuitfor relay 2RA may be traced from the positive supply terminal throughfront contact 34 of relay P, conductor 48, engaged contacts 42 and 43 ofrelays 4R, 3RA and 3R in series, engaged contacts 42 and 4| of relay2RA, conductor 54 and the winding of relay 2RA back to the negativesupply terminal.

The code-following operations on the part of track relay TR which havejust been described and the resulting effect upon the chain relays arecommon to the cycles of all three of the slow, caution and clear codesrepresented in Fig. 2. From this point, however, the or slow codediffers from the other two traffic-governing codes and for this reasonit will first be described separately. This description will be followedby an account of what takes place during the remainder of the caution orI20 code and then by an account of what takes place during the remainderof the I or clear code.

'As the first reversed-polarity energy pulse of the 80 or slow codecycle is received, track relay TR still retains its contact 28 in thereleased position and in other respects the effect is the same as werethe second "off periodof this code to be prolonged for another of asecond. The condition of the counting chain relays thus remainsunchanged and at the expiration offi; of a second from the end'of thesecond normal-polarity pulse of the code cycle the slow-releasecycleregistering relay P releases its contacts. In

moving to the lower position, contact 34 of that relay breaks the stickcircuit for counting relay 2RA which also drops out. All of the chainrelays are now dropped out, their condition being the same as thatassumed for just prior to the beginning of the first normal-polarityenergy pulse of the trackway code cycle.

During the third off period of the received cycle of the 80 or slow?code, which period marks the completion of the code cycle, the contact28 of the track relay TR still remains released. In consequence, thecycle-registering relay P and all of the relays of the counting chainalso remain in condition to receive another cycle of traffic-governingcode.

The effect of a complete cycle of the. I20 or caution code of Fig. 2upon the'counting chain apparatus will now be considered. During thefirst normal-polarity pulse, the first off period, the secondnormal-polarity pulse and the second off period, the effect or action onthe counting chain relays is exactly the same as that for thecorresponding portions of the slow or 80 code cycle. That is, during andat the end of the second off period, cycle-registering relay P is pickedup and chain relay ZRA is also actuated and locked in through its ownstick circuit.

As the third normal-polarity energy pulse of the caution code isreceived from the trackway, the track relay TR again lifts its contact28 to the front position and picks up counting relay 3R over a circuitwhich extends from the positive supply terminal through the contact 28,conductors 35, 46 and 52, back contacts 39 of relays ER, IRA and 2R inseries, front contact 39 of relay 2RA, conductor 55 and the winding ofrelay 3R back to the negative supply terminal. In actuating, relay 3Rfirst completes its own stick circuit at contact 4| and then interruptsthe stick circuit for relay ZRA at contact 43, thereby allowing thatrelay to drop out. The referred to stick circuit for relay 3R may betraced from the positive supply terminal through front contact 34 ofrelay P, conductor 48, engaged contacts 42 and 43 of relays 4R and 3RAin series, engaged contacts 42 and 4I of relay 3R, conductor 55 and thewinding of relay3R back to the negative supply terminal.

During the third off period of the received "caution code cycle, thetrack relay TR again releases its contact 28 and picks up chain relay3RA over a circuit which extends from the positive supply terminalthrough back contact 28 of relay TR, conductor 49, back contacts 40 ofrelays IR, IRA, 2R and ZRA in series, front contact 40 of relay 3R,conductor 56 and the winding of relay 3RA back to the negative supplytermirelay P, conductor '48, engaged contacts 42 and cycle, thecycle-registering relay P releases its contacts due to more than of asecond having elapsed since the last normal-polarity pulse of trackwayenergy. Contact 34 of relay P now breaks the stick circuit for relay 3RAand allows that relay to drop out. All of the chain relays are nowdropped out and the decoding apparatus of which they form a part is incondition to receive another code cycle. N

The effect upon the counting chain relays'of a complete cycle of the I88or clear code, represented at the top of Pig. 2 as consisting of fournormal-polarity energy pulses followed by two reversed-polarity pulses,'will next be considered.

During the first normal-polarity pulse the first off period, the secondnormal-polarity pulse, the second ofi period, the third normal-polaritypulse and the third off period, the actionson the chain relays are thesame as those which have just been described in connection with thecorresponding portions of the caution code cycle.

As the fourth positive pulse of this clear code cycle is received fromthe trackway, the track relay TR again responds, supplies another pulseof energy'to repeater relay P, and picks up chain relay 4R over acircuit'which extends from the positive supply terminal through frontcontact 28of relay TR, conductors 5's, .6 and 52, back contacts 39 ofrelays IR, IRA, 2R, 2RA and 3R in series, front contact 39 of relay 3RA,condu-ctor 57 and the winding of relay 4R back to the negative supplyterminal. In actuatingrelay 4R completes its own stick circuit atcontact 4! and then interrupts the stick circuit for relay 3RA atcontact 43, thereby allowing that relay to drop out. The referredtostick circuit for relay 4R extends from the positive supply terminalthrough front contact 34 of relay P, conductor 48, engaged contacts42'and 4| of relay 4R, conductor 51, and the winding of relay 4R back tothe negative supply terminal.

During the fourth 01f period of the clear or I 8! code cycle, trackrelay TR again drops out. Aside, however, from the interruption of theenergizing circuit for relay P, no other action takes place during thisperiod. As the first being received, the cycle-registering relay Preleases its contacts due to more than of a second having elapsed fromthe end of the last pulse of normal-polarity energy. Contact 34 of thatrelay now breaks the holding circuit for chain relay 4R and that relayaccordingly drops out. During the sixth and final off period of theclear code cycle, all of the chain relays continue in theircontact-released conditions and the decoding apparatus of which theyform a part is again ready to receive and respond to another cycle oftrackway code.

From the foregoing it will be seen that the code-following track relayTR functions to energize the counting-chain relays in sequence duringeach of the trafiic governing code cycles of trackway energy which itreceives from the trackway and that the counting relays, in turn,decipher each received cycle by registering the number ofnormal-polarity pulses which it contains. Thus if there are two of theseper cycle, as in the case of the slow or 80 code, chain relay 2R picksup its contacts; if there are three, as in the case of the caution orI20 code, relay 3R picks up its contacts; and if there are four, as .inthe case of the clear or I89 code, chain relay 4R picks up it'scontacts.

It will also be seen that the pulses of reversedpolarity energy whichfollow each series of norrnal-polarity pulses have the effect ofallowing the relay counting chain to return to normal so that it isprepared to receive the next series of normal-polarity pulses. From thisit will further be apparent that the efiect produced on the 4 countingchain by these reversed-polarity pulses might also be produced by usinga simple time interval of corresponding total length between each seriesof normal-polarity pulses. However, for reasons to later be discussed ingreater detail in connection with the operation of train-carried cabsignaling equipment controlled through the medium of the usual frequencytype of decoder, it is preferred to employ the pulses of reversepolarity in the manner already explained in connection with thecode-cycle representations of Fig. 2.

The manner in which the chain relays control the tr-afiic-governingrelays H, D and DD will now be explained. In the illustrativearrangement shown, relay H responds to cycles of received trackway codeof any one of the slow, caution and clear varities of Fig. 2; relay Dresponds to cycles of the caution and the clear codes only; and relay DDresponds to cycles of the clear or I80 code only.

Each of these trafiic-governing relays is of the slow-releasing type andis represented as having a direct-current operating winding adapted tobe supplied with energizing current through a circuit which is shown asbeing connected with a direct-current supply source, again designated bythe terminals plus and minus. In operation of each relay, even a veryshort pulse of energizing current serves to pick-up the cont-acts (I4, I8 and I9) thereof, which continue tooccupy their front position for thefull release period of the relay after the actuating current isinterrupted. If, of course, within this release period another pulse ofenergizing current is supplied, the time of contact-closure is prolongedfor another release period and the contacts then do not drop out untilthat further period has expired.

As has been pointed out, control of the trafiicgoverning relays iseffected through the medium of contacts 44 carried by the counting chainrelays IR, IRA, 2R, 3R and 4R. The pick-up or energizing circuit forrelay H is carried through contact 44 of relay 2R and can be completedonly when that contact is picked up and the contacts of relays IR andIRA are released. Likewise, the energizing circuit for traffic-governingrelay D is carried through contact 44 of relay 3R and it can becompleted only when that contact is picked up and the contacts of relays2R, IRA and IR are released. And finally, the energizing circuit forrelay DD is carried through contact 44 of chain relay 4R and it can becompleted only when that contact is picked up and the contacts of relays3R, 2R, IRA and IR are released.

All of the energizing circuits for the trafficgoverning relays are, inaddition, dependent for their completion upon contact 28 of the trackrelay TR occupying its front or picked-up position. Moreover, thebefore-mentioned slow-release characteristics of each relay are selectedto be slightly in excess of the cycle lengths of the particulartraffic-governing codes to which that relay responds in order that itmay bridge the gaps between the normal-polarity pulses of successivecycles. Thus in the case of relay H which responds to all three of theslow, caution and clear codes, the longest cycles of which are 2%,seconds in length, the release period is preferably of the order ofabout 2 seconds. In the case of traffic-governing relay D which respondsonly to the caution and the clear codes, for both of which the cyclelengths are 2 seconds, the release period is preferably of the order of2%, seconds. And in the case of traffic-governing relay DD whichresponds only to the clear or I 80 code having cycles of 2 sec ondsduration, a release period of 2 seconds is similarly provided.

The manner in which the just described energizing circuits for thetrafiic-governing relays H, D and DD are selectively completed will nowbe explained. If the slow or 86 code is being received from thetrackway, relay TR picks up, releases, again picks up and then staysreleased for three periods during each cycle of this code, thisoperation repeating itself as long as the named code continues to bereceived. Cycleregistering relay P responds to this operation, itstaying picked up between successive pick-ups on the part of relay TRand dropping out after each pair thereof or between successive codecycles. On the first front contact closure of relay TR chain relay IRpicks up; on the first release of the track relay contact, chain relayIRA picks up; and on the second front closure of the track relaycontact, chain relay 2R picks up.

Each time that relay 2R is thus actuated, en.- ergizing current issupplied to the winding of traffic-governing relay H through a circuitwhich extends from the positive supply terminal, through front contact28 of relay TR, conductors 3'6, 46 and 52, back contact 44 of relay IR,conductor 6|, (also front contact 59 of relay TP and conductor I3 inFig. la) back contact 44 of relay IRA, front contact 44 of relay 2R,conductor 62, and the winding of relay H back to the negative supplyterminal. Due to its slow release characteristics relay H bridgessuccessive cycles of the slow or 80 code and thus maintains its contactscontinuously picked up as long as that code is received from thetrackway.

When the caution or I20 code is received, the track relay TR picks up,releases, picks up, releases, and picks up and then releases and stayscessive code cycles.

released for three successive periods during each cycle of that code.

ing of traffic-governing relay H receives current through the circuitjust traced and thus maintains its contacts continuously picked up aslong as the caution code is received. Each time that chain relay 3Rcloses its front contacts, the winding of traffic-governing relay Dlikewise receives a pulse of energizing current through a circuit whichmay be traced from the positive supply terminal through front contact 28of relay TR, conductors 36, 46 and 52, back contacts 44 of relays IR,IRA (interconnected in Fig. 1b by conductor 6|; in Fig. ill, byconductor 6|, front contact 59 of relay TP and conductor 13) and 2R inseries, front contact 44 of relay 3R, conductor 63, and the winding ofrelay D back to the negative supply terminal. Due to its slow'releasecharacteristics relay D also maintains its contacts continuously pickedup as long as the caution 7 code is received from the trackway.

When the clear or I80 code is received from 7 the trackway, relay TRpicks up, releases, picks up, releases, picks up, releases, picks up andthen releases and stays released for five periods during each cycle ofthat code. The repeater relay P maintains its contacts picked up duringeach series of the four pick-up operations on the part of relay TR andreleases them after each series or between succesive code cycles. On thefirst pick-up operation by relay TR chain relay IR picks up; on thesecond chain relay 2R picks up; on the third chain relay 3R picks up;and on the fourth chain relay 4R picks up.

Each time relay 2R thus is energized the winding of traffic-governingrelay H receives a pulse of energizing current; each time that relay 3Rpicks up the winding of traffic-governing relay D receives an energizingpulse; and each time that relay 4R picks up the winding oftraffic-governing relay DD likewise receives an energizing pulse. Thepick-up circuits for relays H and D are the same as those traced above.In the case of relay DD the circuit extends from the positive supplyterminal through front contact 28 of relay TR, conductors 3'6, 46 and52, back contacts 44 of relay IR, IRA (interconnected in Fig. 11) byconductor 6I; in Fig. 1a by conductor 6 I front contact 59 of relay TPand conductor 13), 2R and 3R in series, front contact 44 of relay 4R,conductor 64 and the winding of relay DD back to the negative supplyterminal. Due to their slow release characteristics all three of thesetrafiic-governing relays H, D and DD continuously maintain theircontacts picked up as long as the clear code is received from thetrackway.

When no energy is received from the trackway, contact 28 of track relayTR remains in the released position, the contacts of all seven of thecounting chain relays IR to 4R are likewise dropped out, and all threeof the traffic-governing relays H, D and DD also allow their contacts tooccupy the released positions.= This comes about from the fact thattheir pick-up circuits are respectively broken at the contacts 44 ofrelays 2R, 3R and 4R which are, under the conditions stated,continuously released.

The equipment so far described is that which is associated with trackblocks which do not contain cut sections and of which the apparatusrepresented at location M in Fig. 1b is representative. It is to benoted that no line conductors are required between the equipment at theentrance ends of successive blocks not containing cut sections, the onlymedium of inter-connection being the track circuit of which thetrafiicrails I and 2 form a part.

When, however, a block includes, as does that shown at LM, a cut sectionof the character defined by location La, certain additional equipment isrequired. As represented in association with location La, thissupplemental equipment includes provision for repeating the trackwaycode around the insulated joints 3 of the cut section, a coding deviceCTa; for supplying the rear track circuit with energy of the specialdetection code previously referred to, and relays XR and associatedmeans for controlling the highway-crossing signals XS.

The code-repeating provisions will first be described. As shown atlocation La, these take the form of a track transformer TTa connectedwith the rails of track section LLa, a supply transformer B constantlyenergized from the alternating current source BC and having a secondarywinding provided with normal and reversed polarity energy-supplysections, and a pair of track relays TRN and TRR' connected with therails at the entrance end of the section LaM and provided with contacts66 through which either the normal or the reversed polarity sec tion ofthe supply winding may be connected with the primary of the tracktransformer TTa through the medium of conductor I2 and a contact 61 of arelay TPa.

Track relay TRN is substantially a duplicate of the device TR atlocations L and M and is arranged to pick up its contacts when thecontrol winding thereof'receives trackway energy which has a normalrelative instantaneous polarity with respect to the voltage from sourceB-C which constantly energizes with the exciting winding 2! of therelay. At all other times the relay contacts 28 and B6 occupy thereleased position. The second track relay TRR is of similar constructionand characteristics. It differs from the first, however, in beingarranged, as by a reversal of the supply connection for the excitingwinding 21, to pick up its contacts in response to trackway energy ofreversed relative instantaneous polarity and to allow the contacts toremain in the released position at all other times.

In operation, relay TRN follows the normalpolarity pulses of codedenergy which are transmitted thereto by the rails of track section Liz-N, while relay TRR similarly follows the reversedpolarity pulseswhich'are impressed upon its control winding. Hence, as long as therails of the forward track section LaM transmit no energy to these twotrack relays, the contacts of both occupy their dropped out positionsand the supply transformer 8 then is disconnected from the tracktransformer TTa. at contacts 66. Under this condition no energy issupplied to the track section L-La to the rear.

However, upon the occasion of each normalpolarity pulse of energyreceived by the relays TRN and TRR at location La, relay 'IRN picks upits contacts and relay 'I'RR tends to move its contacts furtherdownwardly. Contact 65 of relay TRN now connects the primary of tracktransformer T'Ia with the upper half of the secondary winding of supplytransformer 8 and completes a rail-supply circuit which extends from theupper terminal of the secondary of transformer 8 through conductor 29,front contact 66 of relay TRN, conductor 68, front contact 67 of relayTPa, conductor 12, the primary of track transformer TTa, and conductorI! back to the mid-tap 9 of the supply winding. Through this circuit thetrack section to the rear of location La is supplied withnormal-polarity energy as long as the contacts of track relay TRN remainpicked p.

Similarly, when the forward section transmits alternating current energyof the reversed polarity, track relay TRR responds and picks up itscontacts, thereby completing at contact 66 a circuit through which thetrack transformer TTa is connected with the lower half of the secondarywinding of the supply transformer 8. This circuit may be traced from thelower terminal of the supply winding through conductor 30, front contact66 of relay TRR, conductor 68, front contact B7 of relay TPa, conductorl2, the primary of track transformer TTa, and conductor ll back to themid-tap 9 of the supply winding. Through it the track section to therear of location La is supplied with reversed-polarity energy as long asthe contacts of track relay 'IRR remain picked up.

In this manner, the coded energy which is received from the rails oftrack section La-M is at all times repeated in the rear section L-La,not only as to on and off periods of the code but also as to therelative instantaneous polarity of the voltage of which each energypulse of this code is made up. Insofar, therefore, as the effect uponthe equipment at location L by energy supplied to the rails throughtrack transformer TT at location M is concerned, each one of the codesshown in Fig. 2 is repeated around the cut section La and thustransmitted to location L in the same manner as were rails betweenpoints L and M in the form of the continuous conductors of the trackblocks which do not contain cut sections.

The manner in which the highway crossing signals XS associated with thecut section La are controlled will now be described. In the schemeshown, two relays XRi and XR2 are utilized jointly to control thecompletion of the highway signal operating circuit and thus determinethe operation of the crossing protective signals. Each of these relaysis provided with a contact 69 through which operating energy may besupplied to the signals. Through the medium of a pawl device (notshown), these contacts are so interlocked mechanically that only one ofthem may occupy its downward or circuit-completing position at anyparticular time. Moreover, this pawl operates further to require thatfollowing a contact release on the part of either of the relays XR thewinding of the companion relay must be energized before the contact ofthat relay can be released to its circuit-closing position.

Normally the windings of both of these relays receive energizing currentthrough circuits which respectively include contacts "H and 12 of relaysTP and TPa at locations L and La and thus hold the contacts 69 in thepicked-up positions represented. Under such conditions the crossingsignals XS do not operate. When, however, either of these two circuitsis interrupted, the affected relay XR releases its contact 69 andthereby brings the crossing signals XS into operation.

Also forming a part of the crossing-signal control apparatus at locationL is the previously mentioned special cycle-registering relay TP. It isof the delayed-release type and in the scheme disclosed it is arrangedto hold its contacts in their picked-up position for a period, followingeach pulse of energizing current received by its operating winding,which exceeds the relatively wide spacing between consecutive energypulses of the detection code which is represented at the bottom of Fig.2. Whenever not only this detection code but also any one of the threetrafl'lc-governing codes also represented in Fig. 2 is received from thetrackway by the track relay TR at location L, this slow-release relay TPmaintains its contacts continuously picked-up and thereby suppliesenergy to relay XRI.

This continuous closure of the front contacts of relay TP results from ajoint action of the cycleregistering relay P and the counting-chainrelay IRA, which action will now be explained. Following each pulse ofnormal-polarity energy, relay P holds its contacts in the picked-upposition for about of a second and thus sets up, at contact 35, thepick-up circuit for relay TP. Also following each of thesenormal-polarity pulses,

counting chain relay RA picks up, in the manner previously explained,and thus completes, at contact M, the just referred to pick-up circuitwhich extends from the positive supply terminal through back contact 28of relay TR, conductor t9, front contact 35 of relay P, conductor 15,front contact of relay IRA, conductor 16 and the winding of relay TPback to the negative supply terminal.

As long, in consequence, as the above circuit completion repeats itselfat intervals not exceeding those determined by the pulse spacings of thedetection code shown in 2, the cycleregistering relay TP at location Lholds its contacts picked-up continuously, this action being madepossible by the before described slowreleasing characteristics of therelay. Under other conditions, of course, as when the track section L-Lais occupied by a train, relay TP releases its contacts.

A corresponding relay TPa, also of the slowreleasing type, is installedat the cut-section location La and arranged to control the energizationof relay XRZ. Energizing current is supplied to the winding of thisrelay TPa through the contact 28 of either of the relays TRN and TRR.That is, in responding to each normalpolarity pulse of trackway energy,relay TRN completes an actuating circuit for relay TPa which may betraced from the positive supply terminal, through front contact 28,conductor Ti and the winding of relay TPa back to the negative supplyterminal. Likewise, in responding to each reversed polarity pulse ofcoded trackway energy, contact 28 of relay TRR completes an equivalentenergizing circuit for the relay TPa.

This relay 'IPa has a contact-release period which is somewhat in excessof the longest off period of any of the three traffic-governing codeswhich may be received at location La. Whenever, therefore, this receivedenergy is of the slow, caution or clear code represented in Fig. 2,relay TPa holds its contacts continuously picked up, due to thereception by its winding of the spaced energizing pulses previouslydescribed. Under other conditions, of course, as when a train is in thesection LaM to by-pass the coded energy supplied to the rails thereof,the relay releases its contacts.

Also installed at location La and aiding in the control of the crossingsignals XS is a special coding device CTa which comes into action atproper times to silence these signals. This code transmitter CTa isrepresented as being of the constantly-operating type and has a codingcontact 2E and operating means therefor which cooperate in producing thepreviously referred to clearing or detection code represented at thebottom of Fig. 2.

This detection code is of a distinctive character which does not causeresponse of the wayside signal S at location L or of cab-signals on afollowing train which may have overrun that location, and yet it iseffective to act upon the relay apparatus at location L in a mannerwhich stops operation of the crossing signals XS. The particular codeillustratively shown at the bottom of Fig. 2 consists of a relativelyshort on period followed by a relatively long off period, these periodsbeing repeated successively. It mayconveniently be produced by contactoperating mechanism of the character represented at the bottom of Fig. 3in asociation 'mal-polarity energy followed by a much longer spacinginterval.

Whenever the advance section LaM is occupied by a train, energy pulsesof the detection code are suppliedfrom the transformer 8 to the tracktransformer TTa and thence to the rails of the track section to the rearof location La. Under the condition stated, relays TRN and TRR are bothdeenergized and contacts of relay TPa are also dropped out. Contact 20of device CTa now periodically completes a rail-supply circuit whichextends from the upper terminal of the secondary winding of transformer8 through con-i 'ductors 29 and I8, coding contact 20, conductor I9,back contact 61 of relay 'I'Pa, conductor I2, the primary winding oftransformer T'Ia and conductor I I back to the mid-tap 9 of the supplywinding.

The effect of the detection code upon the relay apparatus at location Lwill now be considered. As each pulse (which is of normal polarity) ofthis code is received from the trackway, track relay TR responds andsimultaneously picks up repeater relay P and chain relay IR. Relay IRlocks itself in, while relay P holds its contacts picked up during thepulse andfor of a second thereafter. At the end of the pulse,

relay TR releases its contact 28 and picks up chain relay IRA whichlocks itself in. Contact 14 thereof now picks up relay TP by completingthe before-traced energizing circuit for the Wind-.

way crossing signals. XS is prevented by virtue of contact 69 of relayXRI also being picked up. 7

Under the stated conditions, moreover, the contacts of all three of thetrafiic-governing relays H, D and DD at locattion L are released and thecontrolled signal SI accordingly shows stop. This continuouslydeenergized condition of the traffic-governing relays results from thefact that the widely spaced energy pulses of the detection code,impressed upon the track circuit of the cut section L-La by device CTa,are ineffective to pick up any of the counting chain relays above IR andIRA at location L. In so far as relays. H, D and DD are concerned,therefore, the effect is the same as were no energy at all to bereceived from the trackway.

In operation of the complete highway crossing signal control systemherein disclosed, as long as both of the track sections LLa and La-M arevacant the signals XS are inactive. When, however, a train approacheslocation La from either direction these signals are brought intooperation and continue active until the. train either clears thatlocation or withdraws from the track section by which it approached.

In examining this operation, assume first that a train proceeding alongtrack l-2 in the authorized direction of the arrows enters sectionIr-Lll. Relay TR at location L releases its concode from location La tolocation L. There this picks up the contact of track relay TR once every3 seconds and effects, in the manner already described, energization ofrelays TP and XRI to discontinue operation of the crossing protectivesignals XS. Even though the second interlocked relay XR2 remainsdeenergized While the train continues through the advance section LaM,that relay does not close the operating circuit'of the crossing signalsXS for the reason that the before-described interlocking pawl nowfunctions mechanically to hold the contact 69 thereof out of engagementwith its back point.

When the forward moving train clears the exit end of this advancesection La-M, energy of one or another of the clear, caution and slowcodes is received at location La and repeated by relays TRN and TRR inthe rear section L-La;

the contacts of relay TPa are picked up under the control of thisrepeated energy; and the energizing circuit for relay XR2 is again,completed. Under these conditions the interlocking V pawl returns to aneutral position which allows either one of the two relays XRI, ifsubsequently deenergized, selectively to drop its. contact 69 to thecircuit-closing position and again place the crossing signalsXS inoperation.

Consider next that a train going in the reverse direction backs into theexit end of track section LaM. At location La, relays TRN and TRR. nowrelease their contacts, as does also relay TPa upon the expiration ofits. delayed-release period. Contact I2 thereof breaks the energizingcircuit of relay XR2 which, in turn, places the crossingprotectivesignals XS in operation. This opera- 7 5 tion continues as long as anypart of the named train remains in section LaM.

As soon as the reverse-moving train backs out of the entrance end ofsection La-M, the rails of that section again transmit coded energy fromlocation M to location La. There this is responded to by relays TRN andTRR which effect the energization of relay TPa. In consequence,operation of the crossing protective signals XS is now discontinued byrelay XR2. Even though the companion relay XRJ remains dcenergized whilethe train is in track section LLa, contact 69 of that relaydoes not dropto its circuit-closing position for the reason that the interlockingpawl now holds that contact out of engagement with its back point.

Should the reverse-moving train clear the entrance end of this rearsection LLa, one or another of the traffic-governing codes is thenreceived at location L, the contacts of relay TP are again picked up,and theenergizingcircuit for relay XRI is once more completed. Thisreturns the interlocking pawl to its before-described neutral position.

The Various component parts of my improved signaling apparatus havingbeen described, attention will now be directed to the manner ofoperation of the complete system shown in the diagram of Figs. la-b. Tofacilitate a description of this operation, the diagram of Fig. 4 hasbeen prepared and will be referred to as the description proceeds. Init, the track |2 of Figs. la-b is represented as extending for threeblocks (identified with locations K, J and I) behind the wayside signallocation L, and a train V is shown as occupying the portion of thesignal block LM immediately ahead of the cut section La.

Under these conditions, and further assuming that at least three blocksahead of section La.1VI are clear, the wayside apparatus at location Mreceives trackway energy of the clear code reprepresented at the top ofFg. 2, the track relay TR. follows the normal-polaritypulses of thiscode, cycle-registering relay TP holds its contacts in the picked-upposition, the contacts of all three of the traffic-governing relays H, Dand DD are picked up and the signal Sm shows the clear indication ofgreen-over-red.

At the cut-section location La immediately behind the train V, thecontacts of both of the track relays TRN and TRR, are released, as arealso those of relay TPa. This results from the by-passing through thetrain wheels and axles of the energy which is supplied to the trackrails by the track transformer TT at location M. Under the conditionsstated, coding device CTa supplies the rails of section LLa with energyof the detection code represented at the bottom of Fig. 2.

At location L this energy momentarily picks up the contact of trackrelay TR every 3 seconds, causes relay TP to hold its contactcontinuously picked up, and keeps the highway crossing signals XS atlocation La from operating. As the detection code is ineffective forcausing pick-up current to be supplied to the traffic-governing relaysH, D and DD, the contacts of all three of these relays accordinglyremain released. This causes the wayside signal SI to display the stopindication of red-over-red and the associated code transmitter CT tosupply the rails of section K-L with energy of the slow or 80 pulse perminuite code. I

At location K the track relay TR follows the normal-polarity pulses ofthis energyrthe contacts of traffic-governing relay H are picked up andthose of relays D and DD are released. In consequence, the waysidesignal Sic shows the slow indication of yellow-over-red and the rails oftrack section JK are supplied with energy of the caution or 120 pulseper minute code. At location J the track relay TR follows thenormal-polarity pulses of this code, the contracts of traffic-governingrelays H and D are picked up and those of relay DD are released. As aresult the signal Sy' controlled thereby shows the caution indication ofyellow-over-green and the rails of section I-J are supplied with energyof the clear or 180 pulse per minute code.

At location I track relay TR follows the normalpolarity pulses of thiscode and causes the contacts of all three of the trafiic-governingrelays H, D and DD tobe picked up. Under this condition the waysidesignal S1 shows the clear indication of green-over-red and the rails ofthe track section to the immediate rear are supplied with energy of theclear code. At each of the succeeding locations to the rear which areassociated with vacant track sections, the just-described conditions forthe apparatus at location I are repeated.

In addition to providing the just-described advantageous form of waysidesignal control, the frequency-polarized trackway codes used in myimproved system make it possible for train-carried cab-signalingequipment utilizing the usual frequency type of decoders to respond tothe trackway energy in exactly the same manner as were the conventionalfrequency codes (consisting of normal-polarity pulses only) to besupplied to the track rails. Train-carried cab signaling and/or brakecontrol equipments of the type referred to are well known in the art andthe circuits of one illustrative form thereof are represented in Fig. 5.

This typical cab-signaling equipment of Fig. 5 is generally equivalentto that shown and described in United States Patent No. 1,773,472 toPaul N. Bossart, which issued August 19, 1930, from an applicationSerial No. 166,407, filed February 7, 1927, and assigned to The UnionSwitch 8!. Signal Co. It makes use of pick-up windings 85 and 86 mountedon the locomotive from, an amplifier 81 which strengthens the energyinductively received from the track rails i and 2 by these windings, amaster or code-following relay MR which is energized by a measure of theoutput of this amplifier and which responds to each pulse of thetrackway energy regardless of its relative instantaneous polarity, adecoding transformer DT which is supplied under the control of. themaster relay with code-following pulses of primary current, decodingrelays DRl8ilDRl2il and DRI-I which are connected with the decodingtransformer through frequency-selective circuits B9 and whichselectively respond in accordance with the frequency of the voltageappearing in the transformer secondary, and a cab signal CS V' in thesection LaM. Of this signal CS, the top unit or lamp is assumed todesignate fullauthorized speed, the second lamp from the topcaution'speed, the third slow speed and the fourth the most restrictiveor stop indication.

When the following or signal-carrying train referred to above isreceiving the clear code of Fig. 2, both the positive or normal-polarityand the negative or reverse-polarity pulses of this code have the sameeifect upon the frequency-selecv.tive decoding apparatus on the'trainand in consequence the two decoding relays DR|80 and DRH'which respondto trackway energy pulses of the I80 code rate pick uptheir contacts andcomplete the energizing circuit for the top lamp of the signal CS.Whenthe train is in a section supplied with energy of the caution codeof Fig. 2, its decoding apparatus again responds in the same manner aswere all of the uniformly spaced energy pulses to be of the samerelative polarity and the decoding relays DRI20 and DRH then respond andcomplete the energizing circuit for the second or caution lamp of thecab signal. When the signal-carrying train is in a section supplied withtrackway energy of the slow code shown in Fig. 2, the decodingapparatusresponds to the 80 pulse per minute rate and the decoding relayDRH only now responds and completes the energizing circuit for the thirdor slow lamp. Finally, when the train-carried apparatus receives uncodedtrackway energy, or no energy at all, all three of the decodingrelays'DR drop out and the most restrictive or stop lamp of the cabsignal is then lighted.

Train-carried apparatus of the character under consideration. is,moreover, unresponsive to the detection code shown at the bottom of Fig.2. Because of the very wide separation of the energy pulses of thiscode, their effect upon the apparatus is the same as were no energy tobe received from'the trackway. That is, even though the master relay MRon the train follows these pulses, the short periods of energizationwhich it causes to be supplied to thedecoding transformer DT are sowidely spaced that none of the decoding relays can respond thereto andthe stop lamp of the cab signal accordingly remains lighted.

From the foregoing it will be seen that the improved organization of thetrackway apparatus of my invention provides all of the advantages whichare incident to previous coded wayside and cab-signal systems. That is,the indicating means of my new system are immune to foreign current, noline conductors are needed to obtain automatic block signaling and noreset or approach-energization problems are involved. Be- 7 cause of itsuse of two element two-position track relays, protection againstbroken-down rail joints may be made inherent. Moreover, the system isequally applicable to automatic signal blocks which both do and do notcontain cut sections and in case out sections are present clearancethereof by a detection code may be effected without in In fact, thecounting chain Hence, although I have herein shown and described onlyone form of railway traflic 'controlling apparatus embodying myinvention, it will be understood that various changes and modificationmay be made therein within the scope of the appended claims withoutdeparting from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track,

means for supplying the rails of said section with recurring cycles ofoneor another of a plurality of difierent code pulse combinations eachof which is made up of spaced pulses of normal-polarity energy indistinctive number followed by reversed-polarity energy in similar pulseform, means for selectively determining which of said different codepulse combinations is supplied to said rails, a track relay connected tosaid rails and arranged to respond only to the normal-polarity pulses ofsaid coded energy which are received therefrom, decoding means governedby said track relay and arranged to register the number of responseswhich that relay makes during each code cycle, traffic-governing relaysarranged to be energized selectively in accordance with the number ofregistrations which said decoding means make during each cycle ofreceived code energy, and signalling apparatus controlled by saidtrafiic governing relays.

2. In combination, a section of railway track, means for supplying therailsof said section with recurring cycles of one or another of aplurality of different code pulse combinations each of which is made upof spaced pulses of normal-polarity energy in distinctive numberfollowed by reversed-polarity energy in similar pulse form,

means for selectively determining which of said' and arranged to respondonly to the normal polarity pulses of said coded energy which arereceived therefrom, a chain of counting relays arranged to register insequence the number of responses which said track relay makes duringeach received code cycle, a cycle-registering relay responsive to theseries of normal-polarity pulses in each cycle and arranged to returnsaid relay counting chain to a pre-registration condition during thereversed-polarity portion of each cycle, traffic-governing relays,circuits controlled jointly by said track and counting-chain relays forselectively energizing said traffic-governing relays in accordance withthe number of registrations which said counting relays make during eachcycle of received code energy, and signalling apparatus controlled bysaid trafiic governing relays.

3. In a railway signaling system, the combination of means for producingrecurring cycles of a plurality of different code pulse combinationseach of which is made up of spaced pulses of normal polarity energy indistinctive number followed by reversed-polarity energy in similar pulseform, a track relay responsive only to the normal-polarity energy, meansfor selectively supplying said track relay with energy cycles of one oranother of said diiferent code pulse combinations, a plurality oftraffic-governing relays having slow release periods sufficient to spanthe time between corresponding pulses in. recurrent cycles of thereceived code, signalling apparatus controlled by said traffic governingrelays, and. means for sequentially actuating a variable number of saidtraffic-governing relays in accordance with the number of responseswhich said track relay makes during each received code cycle, said meanscomprising a chain of counting relays arranged to register saidresponses, a cycle-responsive relay arranged to return said countingchain to a pre-registration condition after each response series, andenergizing circuits for the trafiic-governing relays controlled jointlyby said track and counting chain relays.

4. In a. railway signaling system, a trafiic track, means for supplyingsaid track with recurring cycles of one or another of a plurality ofdifferent code pulse combinations each of which is made up of adistinctive number of normalpolarity pulses separated by time intervalsand followed by a time interval together with reversed-polarity energyin similar pulse form, means for selecting which of said different codepulse combinations is supplied to said track, a track relay connected toreceive said coded energy from said track and arranged to pick up uponeach normal-polarity pulse of that energy and to remain dropped out atall other times, a plurality of counting relays controlled by said trackrelay and arranged to register in sequential order each pick-up and eachdrop-out operation thereof, trafl'lc governing means controlled by saidcounting relays, and a cycle-registering relay for returning saidcounting relays to a preregistration condition after each cycle-seriesof normal-polarity pulse responses of said track relay, saidcycle-registering relay receiving energy upon each pick-up operation ofthe track relay and having a slow release period sufiicient to bridgethe individual spacing intervals in the code cycles but not the combinedtime represented by the reversed-polarity pulses and their associatedintervals which constitute the latter portion of each cycle.

' 5. In a railway signaling system, a traffic track, means for supplyingsaid track with recurring cycles of one or another of a plurality ofdifferent code pulse combinations each of which is made up or" adistinctive number of normal-polarity pulses separated by time intervlsand followed by a time interval and reversed-polarity energy in similarpulse form, means for selecting which of said different code pulsecombinations which is supplied to said track, a track relay connected toreceive said coded energy from said track and arranged to pick up uponeach normal-polarity pulse of that energy and to remain dropped out atall other times, a chain of relays adapted to be energized anddeenergized in sequence and consisting of two groups arranged inalternation, circuits completed when said track relay is picked up forcausing the relays of one of said groups to register the number ofnormal-polarity pulses in each cycle of coded energy, other circuitscompleted when said track relay is dropped out for causing the relays ofsaid other group to register the number of time periods in each cyclewhich separate normal-polarity pulses, a slow-release cycle-registeringrelay receiving energy upon each pick-up operation of the track relayand acting to return said chain relays to a pre-registration conditionafter each cycle series of normal-polarity pulses, and traific governingmeans controlled by said chain relays.

6. In combination, a first and a second section of railway track, meansfor supplying the rails of said first section with spaced pulses of bothnormal and reversed-polarity energy, a first polar relay receiving saidenergy from said rails and responsive only to the normal-polarity Pulsesthereof, a second polar relay also receiving said energy from said railsbut responsive only to the reversed-polarity pulses thereof, a circuitthrough which energy may be supplied to the rails of said second tracksection, sources of normal and reversed-polarity energy, a contactcarried by said first polar relay for connecting said rail-supplycircuit to said normal-polarity source upon each response of that relay,and a contact carried by said second polar relay for connecting saidrailsupply circuit to said reversed-polarity source upon each responseof that relay.

7. In combination, a first and a second section of railway track, afirst and a second codefol lowing polar relay connected to the rails ofsaid first section and respectively responsive to normal andreversed-polarity energy pulses which may be received therefrom, acircuit through which energy may be supplied to the rails of said secondtrack section, a source of energy, a coding device having a contactwhich periodically establishes connection with said source in a mannerto produce recurring code cycles each consisting of a connection periodfollowed by a much. longer spacing interval, a slow-release relayjointly controlled by said two polar relays, and means including saidslow-release relay for connecting said rail-supply circuit Whenever bothof said polar relays remain inactive for the prolonged period whichaccompanies the presence of a train in said first track section.

8. In combination, a first and a second section of railway track, afirst and a second code-following polar relay connected to the rails ofsaid first section and respectively responsive to normal and reversedpolarity energy pulses which may be received therefrom, a circuitthrough which energy may be supplied to the rails of said second tracksection, a source of energy, a coding device having a contact whichperiodically establishes connection with, said source in a manner toproduce recurring code cycles each consisting of a connection periodfollowed by a much longer spacing interval, a slow-release relay havinga contact which in its dropped out position connects said rail supplycircuit with said energy source over said coding contact, and contactscarried by said polar relays and arranged to sup ply pick-up current tosaid slow-release relay whenever either of said polar relays is pickedup.

9. In combination, a first and a second section of railway track, afirst and a second code-following polar relay connected to the rails ofsaid first section and respectively responsive to normal andreversed-polarity energy which may be received therefrom, a circuitthrough which energy may be supplied to the rails of said second tracksection, sources of normal and reversedpolarity energy, contacts carriedby said and second polar relays for connecting said railsupply circuitrespectively to said normal and reversed polarity sources upon eachrespective response of the polar relays whereby to repeat into the railsof said second section each pulse of both normal and reversed-polarityenergy which may be received from the rails of said first section, acoding device having a contact which periodically establishes connectionwith said normal-polarity source in a manner to produce recurring codecycles each consisting of a connection period followed by a much longerspacing interval, and a slow-release relay jointly controlled by saidtwo polar relays and arranged to connect said rail-supply circuit withsaid energy source'over said coding contact whenever'both of said polarrelays remain dropped out for the prolonged period which accompanies thepresence of a train in said first track section.

10. In combination, two consecutive sections of railway track, highwaycrossing protective apparatus positioned adjacent the point of divisionbetween said track sections, a relay arranged when unenergized to placesaid protective apparatus in operation, a slow-release relay arrangedwhen picked up to supply energizing current to said operation-governingrelay, and a pair of code-following polar relays connected to the railsof one of said track sections and respectively arranged to supplypicked-up current to said slowrelease relay whenever energy of normal orreversed relative polarity is received from said rails, I

11. In combination; a first and a second section of railway track, meansfor supplying the rails of said first'section with pulses of codedenergy which regularly recur and which are separated by time intervalsof relatively short dura tion, means for repeating said pulses into therails of said second section, means effective when no energy is receivedfrom the rails of said first section for supplying the rails of saidsecond section with recurring code cycles each consisting of an energypulse followed by a relatively long spacing interval which longerinterval substantially exceeds the said relatively short intervals thatseparate the said pulses of coded energy which are suppliedeto the firstsection, highway crossing protective apparatus located adjacent thepoint or" division between said track sections, a relay arranged whenunenergized to place said apparatus in operation, a slow-release relayar ranged when picked up to supply energizing current to saidoperation-governing relay, and means controlled by coded energy receivedfrom the rails of said second section for maintaining said slow-releaserelay continuously picked up as long as the pulses of such receivedenergy recur at intervals which do not exceed the said relatively longspacing interval of the above-described code cycle.

12. In combination, a section of railway track, means at the exit end ofsaid section efiective at times to supply the rails thereof withrecurring pulses of energy which are spaced comparatively closely and inaccordance with one or another of a plurality of difierenttrams-governing code patterns, means also at said section exit effectiveat other times to supply said rails with recurring energy pulses whichare spaced comparatively widely and in accordance with a detection codepattern, traffic-governing apparatus at the en said detection codepulses and. arranged when picked up to supply energizing current to saidoperation-governing relay, and means responsive to pulses of both thedetection and the trafficgoverning codes which may be received from saidrails for supplying said slow-release relay with pulses of pick-upcurrent which recur at intervals less than the release period of thatrelay.

13. In combination with a section of railway track, means at the exitend of said section for supplying the rails thereof with recurringcycles of one or another of a plurality of different codepulsecombinations each consisting of a predetermined number ofnormal-polarity energy pulses which recur at a predetermined rate andwhich are separated by time intervals and followed by a tim intervaltogether with reversed-polarity energy in similar pulse form, means forselectively determining which of said different code pulse combinationsis supplied to said rails, wayside trafiic-governing means at theentrance end of the section controlled by energy received from saidrails and selectively responsive to the number of normal-polarity pulseswhich are present in the cycles of that energy, and train-carriedtraiiic-governing means also controlled by energy received from saidrails but selectively responsive to the rate of recurrence of theindividual pulses of thatenergy.

14 In combination with a section of railway track, means for supplyingthe rails of said section with recurring cycles of one or another of aplurality of diiferent code pulse combinations each of which is made upof a predetermined number of normal-polarity energy pulses which recurat a predetermined rate and which are separated by time intervals andfollowed by a time interval together 'with reversed-polarity energy insimilar pulse form, means for selectively determining which of saiddifierent code pulse combinations is supplied to said rails, and waysidetrafllc governing means at the entrance end of the section controlled bysaid coded energy received from said rails and variably responsive, onlyto changes in the number of normal-polarity pulses which are present inthe cycles of that energy,

15. In combination with a section of railway track, means at the exitend of the section for supplying the rails thereof with recurring cyclesof one or another of a plurality of diiferent code pulse combinationseach consisting of a plurality of normal-polarity energy pulses whichrecur at a predetermined rate and which are separated by time intervalsand followed by a time interval together with reversed-polarity energyin similar pulse form, means for selectively determining which of saiddifferent code pulse combinations is supplied to said rails, andtrain-carried signalling means governed by said coded energy receivedfrom said rails and variably responsive only to changes in the rate ofrecurrence of the individual pulses of that energy.

16. In combination with a section of railway track, means at the exitend of 'said section for supplying the rails thereof with recurringcycles of one or another of a plurality of different code pulsecombinations each consisting of a predeterpulse combinations is suppliedto said rails, way- 75 side traffic-governing means at the entrance endof the section controlled by said coded energy received from said railsand arranged to respond to the number of normal-polarity pulses whichare present in the said cycles thereof and to be insensitive to the rateof recurrence of the individual pulses of which those cycles consist,and train-carried governing means also controlled by said coded energyreceived from said rails but arranged to respond to the said rate ofindividual pulse recurrence and to be insensitive to the polarity of theenergy of said individual pulses.

17. In combination with a section of railway track, a circuit throughwhich energy may be supplied to the rails of said section, a source ofnormal-polarity energy and a source of reversedpolarity energy, aplurality of coding contacts each of which is movable from an inactiveposition either to a first active position in which it establishesconnection with one of said sources or to a second active position inwhich it establishes connection with the other of said sources, meansfor selectively including one or another of said coding contacts in saidrail supply circuit, and actuating means associated with each of saidcontacts for selectively moving that contact between its said inactiveposition and its said two active positions at a distinctive rate and ina cyclic manner whereby the contact produces recurring code patterns ofnormal-polarity connections in a distinctive number followed by a timeinterval and similarly separated reversedpolarity connections.

18. In combination, a section of railway track, a circuit through whichenergy may be supplied to the rails of said section, a source ofnormalpolarity energy and a source of reversed-polarity energy, aplurality of coding contacts each of which is movable from an inactiveposition either to a first active position in which it establishesconnection with one of said sources or to a second active position inwhich it establishes connection with the other of said sources, meansassociated with each of said contacts for selectively moving thatcontact between its said inactive position and its said two activepositions in a cyclic manner whereby the contact produces recurring codepatterns of normal-polarity connections in a distinctive numberseparated by time intervals and followed by a time interval andsimilarly separated reversed-polarity connections, and a group of relayscontrolled by advance trafiic conditions and arranged selectively toinclude one or another of said coding contacts in said rail supplycircuit.

19. In combination, a forward and a rear section of railway track, meansassociated with each of said sections for supplying the rails of thatsection with recurring cycles of one or another of a plurality ofdifferent code pulse combinations each of which consists of spacedpulses of nor mal-polarity energy in a distinctive number followed byreversed-polarity energy in similar pulse form, means for selectivelydetermining which of said different code pulse combinations is suppliedto said forward section rails, a plurality of traflicgoverning relays atthe location of the said supply means for said rear section havingslow-release periods suffi cient to span the time between correspondingenergy pulses of successive forward section code cycles, means governedin accordance with how many of said relays are picked up for selectingwhich of said different code pulse combinations is supplied to the railsof said rear section, and means controlled by said coded energy receivedfrom the rails of said forward section for sequentially energizing saidtrafiic governing relays in response to successive normalpolarity pulsesof each cycle of said coded energy and in such manner that the samerelay receives the same sequential pulse of each normal-polarity seriesand is thereby maintained picked up as long as cycle series containingthat pulse continue to be received from said forward section rails.

20. In combination with a section of railway track, means for supp-lyingthe rails of said section with recurring series of one or another of aplurality of different code pulse combinations each of which consists ofspaced pulses of normal-polarity energy in distinctive number followedby reversed-polarity energy in similar pulse form, means controlled byadvance trafiic conditions for selectively determining which of saiddifierent code pulse combinations is supplied to said rails, decodingmeans controlled by said coded energy received from said rails andarranged to register the number of normal-polarity pulses which arepresent in each pulse series of that energy, and trafiic-governing meanscontrolled by said decoding means and selectively responsive to thenumber of registrations made thereby.

CHARLES W. FAILOR.

CERTIFICATE OF CORRECTION. Patent No. 2,169,605. August 15, 19 9.

CHARLES W. FAILOR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 15,sec- 0nd column, line 58 claim 7, after the word "circuit" insert withsaid energy source over said coding contact; page 1h, first column, line21 claim 10, for "picked-up" read pick-up; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed andsealed this 19th day of September, A. D. 1959.

Henry Van Arsdale,

( Acting Commissioner of Patents.

